Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net revenues	$ 39,743	$ 40,945	$ 77,556	$ 91,217
Cost of revenues	17,758	17,716	34,564	37,973
Gross profit	21,985	23,229	42,992	53,244
Operating expenses:
Research and development	22,411	24,711	44,028	57,916
Selling, general and administrative	8,373	7,919	17,137	16,977
Amortization of purchased intangible assets	0	42	0	104
Restructuring	15	(110)	111	1,101
Total operating expenses	30,799	32,562	61,276	76,098
Operating loss	(8,814)	(9,333)	(18,284)	(22,854)
Realized gain on short-term investments and interest income, net	257	393	1,876	729
Other income (expense), net	8	(2,505)	33	(2,526)
Loss before income taxes	(8,549)	(11,445)	(16,375)	(24,651)
Income tax (benefit) provision	(488)	272	(910)	131
Net loss	$ (8,061)	$ (11,717)	$ (15,465)	$ (24,782)	[1]
Basic and diluted net loss per share (in dollars per share)	$ (0.10)	$ (0.15)	$ (0.19)	$ (0.32)
Shares used in calculating basic and diluted net loss per share (in shares)	82,176	78,487	81,680	78,202

[1] The Statement of Cash Flows for the six months ended September 30, 2014 reflects an immaterial revision to correct outstanding payables related to purchases of property and equipment previously included in net cash used for investing activities to net cash used for operating activities. As a result, net cash used for operating activities increased by $0.3 million and net cash used for investing activities decreased by the corresponding amount.